Significance of dimer models describing physical properties in a triclinic solid of tin(II) phthalocyanine
Significance of dimer models describing physical properties in a triclinic solid of tin(II) phthalocyanine
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描述三斜晶系酞菁锡物理性质的二聚体模型的意义
DOI：
10.1039/c2ra21509h
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发表时间：
2012
期刊：
影响因子：
3.9
通讯作者：
Hitoshi Fujimoto
中科院分区：
文献类型：
--
作者：
Michinori Sumimoto;Teruyuki Honda;Yukio Kawashima;Kenji Hori;Hitoshi Fujimoto
为了研究酞菁锡（SnPc）的基态和激发态的固态电子结构，我们从三斜晶系的晶体结构中提取了两种二聚体和一种三聚体作为模型体系.其中一种二聚体在两个SnPc分子之间具有凸构型，另一种二聚体具有凹构型。三聚体由两种构型组成。采用密度泛函理论（DFT）的M06方法对凹型和凸型二聚体和三聚体的几何构型、电子结构和激发能进行了研究.这些模型系统的几何结构进行了优化下的C2 h分子对称性的二聚体和C1下的三聚体。两个锡原子之间的距离进行了优化，分别为6.805和6.374 <$？凹型和凸型二聚体。三聚体中的相应距离分别计算为6.959和6.457 nm。计算的二聚体和三聚体的Sn-Sn距离与晶体的实验值一致。这些模型系统的能量图意味着，每个分子轨道的SnPc单体形成的电子能带具有相对较大的带宽，由于在固态下的强分子间相互作用。三聚体的含时DFT计算很好地再现了所观察到的固态吸收光谱。应当注意，对于两种类型的二聚体计算的激发态的总和很好地再现了对于三聚体的计算结果。从这些结果，可以得出结论，SnPc的固态的电子结构可以通过使用这两个二聚体进行研究。采用ΔSCF方法计算了SnPc单分子、二聚体和三聚体的垂直电离势（IP）。第一个IP从单体到三聚体降低约0.6 eV。
In order to study the solid-state electronic structures for ground and excited states of tin phthalocyanine (SnPc), we extracted two types of dimers and a trimer as model systems from the crystal structure of the triclinic polymorph. One of the dimers had a convex configuration between two SnPc molecules, and the other took a concave one. The trimer consisted of both configurations. The molecular geometries, electronic structures, and excitation energies of the concave- and convex-type dimers and the trimer were investigated using the M06 method of the density functional theory (DFT). The geometries of these model systems were optimized under C2h molecular symmetry for the dimers and under C1 for the trimer. The distances between two Sn atoms were optimized to be 6.805 and 6.374 Å for concave- and convex-type dimers, respectively. The corresponding distances in the trimer were calculated to be 6.959 and 6.457 Å, respectively. The Sn-Sn distances calculated for the dimers and trimer were consistent with the experimental values for the crystal. The energy diagrams of these model systems imply that each molecular orbital of an SnPc monomer forms the electron-energy band with a relatively large bandwidth due to strong intermolecular interactions in the solid state. The time-dependent DFT calculation for the trimer reproduced well the observed absorption spectrum in the solid state. It should be noted that a sum of the excited states calculated for the two types of the dimers reproduces the calculation results for the trimer well. From these results, it would be concluded that the electronic structure of SnPc for the solid state can be investigated by using these two dimers. The vertical values of the ionization potential (IP) were calculated with the optimized structures for the single molecule, two dimers and trimer of SnPc by the ΔSCF method. The first IPs decreased about 0.6 eV from monomer to trimer.